Only index needed: enumerate or (x)range?

user_1105929 0
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If I want to use only the index within a loop, should I better use the range/xrange function in combination with len() 

a = [1,2,3]
for i in xrange(len(a)):
    print i

or enumerate? Even if I won't use p at all? 

for i,p in enumerate(a):
    print i
range enumerate python
8 Answers

I ran a time test and found out range is about 2x faster than enumerate. (on python 3.6 for Win32)

best of 3, for len(a) = 1M

  • enumerate(a): 0.125s
  • range(len(a)): 0.058s

Hope it helps.

FYI: I initialy started this test to compare python vs vba's speed...and found out vba is actually 7x faster than range method...is it because of my poor python skills?

surely python can do better than vba somehow

script for enumerate

import time
a = [0]
a = a * 1000000
time.perf_counter()

for i,j in enumerate(a):
    pass

print(time.perf_counter())

script for range

import time
a = [0]
a = a * 1000000
time.perf_counter()

for i in range(len(a)):
    pass

print(time.perf_counter())

script for vba (0.008s)

Sub timetest_for()
Dim a(1000000) As Byte
Dim i As Long
tproc = Timer
For i = 1 To UBound(a)
Next i
Debug.Print Timer - tproc
End Sub
user_66928980
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